numpy.datetime_as_string#

numpy.datetime_as_string(arr, unit=None, timezone='naive', casting='same_kind')#

将 datetime 数组转换为字符串数组.

参数:
arrdatetime64 的类数组对象

要格式化的 UTC 时间戳数组.

unitstr

None,“auto”或 datetime unit 之一.

timezone{‘naive’, ‘UTC’, ‘local’} 或 tzinfo

显示 datetime 时要使用的时区信息.如果是 ‘UTC’,则以 Z 结尾以指示 UTC 时间.如果是 ‘local’,则首先转换为本地时区,并以 +-#### 时区偏移量为后缀.如果是 tzinfo 对象,则执行与 ‘local’ 相同的操作,但使用指定的时区.

casting{‘no’, ‘equiv’, ‘safe’, ‘same_kind’, ‘unsafe’}

在 datetime 单位之间更改时允许的强制转换.

返回:
str_arrndarray

与 arr 形状相同的字符串数组.

示例

>>> import numpy as np
>>> import pytz
>>> d = np.arange('2002-10-27T04:30', 4*60, 60, dtype='M8[m]')
>>> d
array(['2002-10-27T04:30', '2002-10-27T05:30', '2002-10-27T06:30',
       '2002-10-27T07:30'], dtype='datetime64[m]')

将时区设置为 UTC 会显示相同的信息,但在末尾添加 Z 后缀

>>> np.datetime_as_string(d, timezone='UTC')
array(['2002-10-27T04:30Z', '2002-10-27T05:30Z', '2002-10-27T06:30Z',
       '2002-10-27T07:30Z'], dtype='<U35')

请注意,我们选择了跨越 DST 边界的 datetime.传入一个 pytz 时区对象将打印适当的偏移量

>>> np.datetime_as_string(d, timezone=pytz.timezone('US/Eastern'))
array(['2002-10-27T00:30-0400', '2002-10-27T01:30-0400',
       '2002-10-27T01:30-0500', '2002-10-27T02:30-0500'], dtype='<U39')

传入一个单位将改变精度

>>> np.datetime_as_string(d, unit='h')
array(['2002-10-27T04', '2002-10-27T05', '2002-10-27T06', '2002-10-27T07'],
      dtype='<U32')
>>> np.datetime_as_string(d, unit='s')
array(['2002-10-27T04:30:00', '2002-10-27T05:30:00', '2002-10-27T06:30:00',
       '2002-10-27T07:30:00'], dtype='<U38')

“casting” 可用于指定是否可以更改精度

>>> np.datetime_as_string(d, unit='h', casting='safe')
Traceback (most recent call last):
    ...
TypeError: Cannot create a datetime string as units 'h' from a NumPy
datetime with units 'm' according to the rule 'safe'
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